A City as a Source of Introduction for Tropical Alien Species (Egeria Densa Planch., Pistia Stratiotes L. & Eichornia Crassipes (Mart.) Solms) in Natural Ecosystems with a Temperate Climate

This paper is concerned with the study of ecology and invasive behaviour of southern tropical invaders (Egeria densa, Pistia stratiotes, Eichornia crassipes) in the setting of urban landscape water bodies with a temperate climate (the case of Kyiv, Ukraine). The article explores the role of a city as a source of invasions. It shows that escape from aquaculture (aquariums or decorative ponds) or deliberate release into natural water bodies are the main settlement solution. A brief historical background of these species found in water bodies of Ukraine has been presented. Favourable treatment for modern invasions of pantropical species has been analysed. Phytocoenotic special aspects of the communities formed by these species and ways and possibilities of naturalization of species in natural water bodies have been explored. Production indicators are being analysed.

Glitter Interference On Photosynthetic Rates of A Submerged Macrophyte (Egeria Densa)

This study analyzed the photosynthetic rates (by the light and dark bottle method) of the submerged macrophyte Egeria densa in the presence of three concentrations of glitter: 0.0235 g (T1/T4), 0.0117 g (T2/T5) and 0.0058 g (T3/T6), as well in its absence (control treatment, CT1 and CT2). About 800 apical fragments of E. densa were distributed in 8 subtreatments (4 under light conditions and 4 in the dark to obtain respiration), with 100 specimens in each. The CT showed the highest net photosynthesis rate (PN = gross photosynthetic (PG) rate subtracted from respiration (RD)) of E. densa, with 59.3%, 32.8%, 13.0% higher compared to T1, T2 and T3, respectively. At T3 it was observed the highest mean respiration rate (RE) o E. densa and at T1, the lowest. Comparing PN with RD, we found that the photosynthetic process was, on average 3.5, 2.47, and 2.93 times higher in CT, T1, T2, and T3, respectively. The presence of glitter may have increased the reflectance of water, as it is a suspended particle and reflected light intensely, considering that it is a metal coated particle. Glitter reflects radiation, decreasing the light absorption process, compromising the use of underwater radiation by E. densa. The microplastic interferes with the absorption of light necessary for photosynthetic processes, reducing them, enabling an imbalance in the ecosystem.

Identity of parasitoid wasps (Hymenoptera, Braconidae and Eulophidae) reared from aquatic leaf-mining flies (Diptera, Ephydridae) on invasive Brazilian waterweed Egeria densa in South Africa

The Brazilian waterweed, Egeria densa Planchon, 1849 (Hydrocharitaceae), is an invasive species in South Africa where it is a host plant for the aquatic leaf-miner Hydrellia egeriae Rodrigues-Júnior, 2015 (Ephydridae, Diptera). Efficacy of the biocontrol agent can potentially be affected by parasitoids. Three species of braconid parasitoid wasps were reared from puparia of Hydrellia egeriae. By comparison with the type specimens, these species have been determined to be Ademon lagarosiphonae van Achterberg, 2012 (Braconidae: Opiinae), Chaenusa anervata van Achterberg, 2012 and Chaenusa seminervata van Achterberg, 2012 (Braconidae: Alysiinae: Dacnusini), all previously recorded as parasitoids of an ephydrid dipterous aquatic leaf-miner, Hydrellia lagarosiphon Deeming, 2012, on Lagarosiphon major (Ridley, 1886) Moss ex Wager (Hydrocharitaceae) in South Africa. The chalcidoid, Janicharis africanus Gumovsky & Delvare, 2006 (Eulophidae), was also reared from Hydrellia egeriae and is possibly a hyperparasitoid of the braconids. South Africa is a new country record for J. africanus. We provide comprehensive images of all species including the braconid types and illustrated identification keys to the Afrotropical species of the two braconid genera are also provided. All images and online keys are available on WaspWeb (http://www.waspweb.org).